CONTEMPORARY DOCUMENTS.
The following documents, drawn from the scientific literature of the
time, are placed in chronological order, beginning with the first
memoir published by Philipp Reis himself, in the _Jahresbericht_ of the
Physical Society of Frankfort, for the year 1860-61. Every care has
been taken that the translations here given shall be faithful in every
detail to the originals. All notes and comments by the translator are
distinguished by being enclosed in square brackets.
[=1.=] ON TELEPHONY BY THE GALVANIC CURRENT.
_By_ PHILIPP REIS.
[Translated from the Annual Report (Jahresbericht) of the
Physical Society of Frankfurt-am-Main, for 1860-1861.]
The surprising results in the domain of Telegraphy, have often
already suggested the question whether it may not also be possible to
communicate the very tones of speech direct to a distance. Researches
aiming in this direction have not, however, up to the present time,
been able to show any tolerably satisfactory result, because the
vibrations of the media through which sound is conducted, soon fall off
so greatly in their intensity that they are no longer perceptible to
our senses.
A _reproduction_ of the tones at some distance by means of the
galvanic current, has perhaps been contemplated; but at all events the
practical solution of this problem has been most doubted by exactly
the very persons who by their knowledge and resources should have
been enabled to grasp the problem. To one who is only superficially
acquainted with the doctrines of Physics, the problem, if indeed he
becomes acquainted with it, appears to offer far fewer points of
difficulty because he does not foresee most of them. Thus did I, some
nine years ago (with a great _penchant_ for what was new, but with only
too imperfect knowledge in Physics), have the boldness to wish to solve
the problem mentioned; but I was soon obliged to relinquish it, because
the very first inquiry convinced me firmly of the impossibility of the
solution.
Later, after further studies and much experience, I perceived that my
first investigation had been very crude and by no means conclusive: but
I did not resume the question seriously then, because I did not feel
myself sufficiently developed to overcome the obstacles of the path to
be trodden.
Youthful impressions are, however, strong and not easily effaced. I
could not, in spite of every protest of my reason, banish from my
thoughts that first inquiry and its occasion; and so it happened that,
half without intending it, in many a leisure hour the youthful project
was taken up again, the difficulties and the means of vanquishing them
were weighed,--and yet not the first step towards an experiment taken.
How could a single instrument reproduce, at once, the total actions of
all the organs operated in human speech? This was ever the cardinal
question. At last I came by accident to put the question in another
way: How does _our ear_ take cognizance of the total vibrations of
all the simultaneously operant organs of speech? Or, to put it more
generally: How do we perceive the vibrations of several bodies emitting
sounds simultaneously?
In order to answer this question, we will next see what must happen in
order that we may perceive a single tone.
Apart from our ear, every tone is nothing more than the condensation
and rarefaction of a body repeated several times in a second (at least
seven to eight times[15]). If this occurs in the same medium (the air)
as that with which we are surrounded, then the membrane of our ear will
be compressed toward the drum-cavity by every condensation, so that in
the succeeding rarefaction it moves back in the opposite direction.
These vibrations occasion a lifting-up and a falling-down of the
“hammer” [_malleus_ bone] upon the “anvil” [_incus_ bone] with the same
velocity, or, according to others, occasion an approach and a recession
of the atoms of the auditory ossicles, and give rise, therefore, to
exactly the same number of concussions in the fluid of the _cochlæa_,
in which the auditory nerve and its terminals are spread out. The
greater the condensation of the sound-conducting medium at any given
moment, the greater will be the amplitude of vibration of the membrane
and of the “hammer,” and the more powerful, therefore, the blow on
the “anvil” and the concussion of the nerves through the intermediary
action of the fluid.
The function of the organs of hearing, therefore, is to impart
faithfully to the auditory nerve, every condensation and rarefaction
occurring in the surrounding medium. The function of the auditory nerve
is to bring to our consciousness the vibrations of matter resulting at
the given time, both according to their number and their magnitude.
Here, first, certain combinations acquire a distinct name: here, first
the vibrations become musical _tones_ or _discords_ (Misstöne).
That which is perceived by the auditory nerve, is, therefore, merely
the action of a _force_ affecting our consciousness, and as such may be
represented graphically, according to its duration and magnitude, by a
curve.
[Illustration: Fig. 24.]
Let the line _a, b_, indicate any given length of time, and the
curve above the line a condensation (+), the curve below the line a
rarefaction (-), then every ordinate erected at the end of an abscissa
will give [according to the height of it], at a moment indicated by the
position of the foot of the ordinate, the strength of the condensation
that is causing the drum-skin to vibrate.
Our ear can perceive absolutely nothing more than is capable of
being represented by similar curves, and this method is completely
sufficient to bring before our clear consciousness every tone and every
combination of tones.
If several tones are produced at the same time, then the medium that
conducts sound is placed under the influence of several simultaneous
forces; and the two following laws hold good:--
If all the forces operate in the same sense, the resultant motion is
proportional in magnitude to the sum of the forces.
If the forces operate in opposite senses, the resultant motion is
proportional in magnitude to the difference of the opposing forces.
Let us exhibit the condensation-curves for three tones--each singly
(Table I.)[16]: then, by adding together the ordinates corresponding
to equal abscissæ, we can determine new ordinates and develop a new
curve which we may call the combination-curve [or resultant curve].
Now this gives us just exactly what our ear perceives from the three
simultaneous tones. It ought to cause us as little wonder that a
musician can recognize the three tones, as that (as is the fact) a
person conversant with the science of colour, can recognize in green,
blue and yellow tints. The combination-curves of table I. present,
however, very little difficulty, since in them all the proportions of
the component curves recur successively. In chords consisting of more
than three tones (Table II.), the proportions of the components are no
longer so easy to recognize in the drawing. But it is also difficult to
an accomplished musician, in such chords to recognize the individual
notes.
Table III. shows us a discord. Why discords affect us so unpleasantly I
leave provisionally to the contemplation of the gentle reader, as I may
perhaps return to this point in another memoir.
It follows from the preceding that:--
(1.) Every tone and every combination of tones evokes in our ear, if
it enters it, vibrations of the drum-skin, the motions of which may be
represented by a curve.[17]
(2.) The motions of these vibrations evoke in us the perception
(sensation) of the tone: and every change in the motion must change the
sensation.
As soon, therefore, as it shall be possible at any place and in any
prescribed manner, to set up vibrations whose curves are like those
of any given tone or combination of tones, we shall receive the same
impression as that tone or combination of tones would have produced
upon us.[18]
Taking my stand on the preceding principles, I have succeeded in
constructing an apparatus by means of which I am in a position to
reproduce the tones of divers instruments, yes, and even to a certain
degree the human voice. It is very simple, and can be clearly explained
in the sequel, by aid of the figure:
[Illustration: Fig. 25.]
In a cube of wood, _r s t u v w x_, there is a conical hole, _a_,
closed at one side by the membrane _b_ (made of the lesser intestine
of the pig), upon the middle of which a little strip of platinum is
cemented as a conductor of the current [or electrode]. This is united
with the binding-screw, _p_. From the binding-screw _n_ there passes
likewise a thin strip of metal over the middle of the membrane, and
terminates here in a little platinum wire which stands at right angles
to the length and breadth of the strip.
From the binding-screw, _p_, a conducting-wire leads through the
battery to a distant station, ends there in a spiral of copper-wire,
overspun with silk, which in turn passes into a return-wire that leads
to the binding-screw, _n_.
The spiral at the distant station is about six inches long, consists
of six layers of thin wire, and receives into its middle as a core
a knitting-needle, which projects about two inches at each side. By
the projecting ends of the wire the spiral rests upon two bridges of
a sounding-box. (This whole piece may naturally be replaced by any
apparatus by means of which one produces the well-known “galvanic
tones.”)
If now tones, or combinations of tones, are produced in the
neighbourhood of the cube, so that waves of sufficient strength
enter the opening _a_, they will set the membrane _b_ in vibration.
At the first condensation the hammer-shaped little wire _d_ will
be pushed back. At the succeeding rarefaction it cannot follow the
return-vibration of the membrane, and the current going through the
little strip [of platinum] remains interrupted so long as until the
membrane, driven by a new condensation, presses the little strip
(coming from _p_) against _d_ once more. In this way each sound-wave
effects an opening and a closing of the current.
But at every closing of the circuit the atoms of the iron needle
lying in the distant spiral are pushed asunder from one another.
(Müller-Pouillet, ‘Lehrbuch der Physik,’ see p. 304 of vol. ii. 5th
ed.). At the interruption of the current the atoms again attempt
to regain their position of equilibrium. If this happens then in
consequence of the action and reaction of elasticity and traction,
they make a certain number of vibrations, and yield the longitudinal
tone[19] of the needle. It happens thus when the interruptions and
restorations of the current are effected relatively slowly. But if
these actions follow one another more rapidly than the oscillations due
to the elasticity of the iron core, then the atoms cannot travel their
entire paths. The paths travelled over become shorter the more rapidly
the interruptions occur, and in proportion to their frequency. The iron
needle emits no longer its longitudinal tone, but a tone whose pitch
corresponds to the number of interruptions (in a given time). But this
is saying nothing less than that _the needle reproduces the tone which
was imparted to the interrupting apparatus_.
Moreover, the strength of this tone is proportional to the original
tone, for the stronger this is, the greater will be the movement of the
drum-skin, the greater therefore the movement of the little hammer, the
greater finally the length of time during which the circuit remains
open, and consequently the greater, up to a certain limit, the movement
of the atoms in the reproducing wire [the knitting needle], which we
perceive as a stronger vibration, just as we should have perceived the
original wave.
Since the length of the conducting wire may be extended for this
purpose, just as far as in direct telegraphy, I give to my instrument
the name “_Telephon_.”
As to the performance attained by the Telephone, let it be remarked,
that, with its aid, I was in a position to make audible to the members
of a numerous assembly (the Physical Society of Frankfort-on-the-Main)
melodies which were sung (not very loudly) into the apparatus in
another house (about three hundred feet distant) with closed doors.
Other researches show that the sounding-rod [i.e. the knitting needle]
is able to reproduce complete triad chords (“Dreiklänge”) of a piano on
which the telephone [i.e. the transmitter] stands; and that, finally,
it reproduces equally well the tones of other instruments--harmonica,
clarionet, horn, organ-pipes, &c., always provided that the tones
belong to a certain range between _F_ and _f''_[20].
It is, of course, understood that in all researches it was sufficiently
ascertained that the direct _conduction_ of the sound did not come
into play. This point may be controlled very simply by arranging at
times a good shunt-circuit directly across the spiral [i.e. to cut the
receiving instrument out of circuit by providing another path for the
currents of electricity], whereby naturally the operation of the latter
momentarily ceases.
Until now it has not been possible to reproduce the tones of human
speech with a distinctness to satisfy everybody. The consonants are for
the most part tolerably distinctly reproduced, but the vowels not yet
in an equal degree. Why this is so I will endeavour to explain.
According to the researches of Willis, Helmholtz, and others, vowel
sounds can be artificially produced by causing the vibrations of one
body to reinforce those of another periodically, somewhat after the
following scheme:--
[Illustration: Fig. 26.]
An elastic spring is set in vibration by the thrust of the tooth of a
cog-wheel: the first swing is the greatest, and each of the others is
less than the preceding one (see Fig. 26).
After several vibrations of this sort (without the spring coming to
rest) let another thrust be given by the tooth; the next swing will
again be a maximum one, and so on.
The height or depth of the sound produced in this fashion depends
upon the number of vibrations made in a given time; but the quality
of the note depends upon the number of variations of amplitude
(Anschwellungen) occurring in the same time.
Two vowels of equal pitch may be distinguished from each other somewhat
after the manner represented by the curves (1) (2): while the same tone
devoid of any vowel quality, is represented by curve (3).
[Illustration: Fig. 27.]
Our organs of speech create the vowels probably in the same manner by a
combined action of the upper and lower vocal chords, or of the latter
and of the cavity of the mouth.
Now my apparatus gives the number of the vibrations, but with far less
strength than the original ones; though also, as I have cause to think,
always proportional to one another up to a certain degree. But because
the vibrations are throughout smaller, the difference between large
and small vibrations is much more difficult to recognize than in the
original waves, and the vowel is therefore more or less indefinite.
Whether my views with respect to the curves representing combinations
of tones are correct, may perhaps be determined by aid of the new
phonautograph described by Duhamel. (See Vierordt’s ‘Physiology,’ p.
254.)
There may probably remain much more yet to be done for the utilisation
of the telephone in practice (zur praktischen Verwerthung des
Telephons). For physics, however, it has already sufficient interest in
that it has _opened out_ a new field of labour.
Philipp Reis.
Friedrichsdorf, near Frankfort-on-the-Main,
in December 1861.
[Though the foregoing memoir, as printed in the ‘Jahresbericht,’ of the
Physical Society of Frankfort-on-the-Main, is dated “December 1861,” it
was delivered verbally on October 26th preceding, as the ‘Proceedings’
of the Society show. From the ‘Jahresbericht’ for the succeeding year
we learn that three weeks after the delivery of this communication
Reis made a second communication to the Society on a kindred matter.
The entry is as follows (‘Proceedings’ of the Society, p. 13): “On the
16th November, by the same: Explanation of a new Theory concerning the
Perception of Chords and of Timbre (‘Klangfarben’), as a Continuation
and Supplement of the Memoir on the Telephone.” So far as can now
be learned, the substance of this communication was embodied in the
latter part of the paper “On Telephony,” when written out in December
for publication. On the 8th of January, 1862, the formal thanks of the
Society were voted to Reis for the manuscript which he had contributed
to the ‘Jahresbericht.’
It is of interest, moreover, to note that the matter did not
immediately drop. Professor Böttger, who as one of the regular
lecturers of the Physical Society, held fortnightly discourses on
matters of scientific novelty, took occasion on the 7th of December
to recur to the subject then attracting so much attention. The title
of his discourse (see ‘Proceedings’ of the Society, p. 11) was
“Application of an Experiment relating to the Transmission of Musical
Tones to any desired distance by means of the Galvanic Current.”
It is not quite certain whether Reis was present on this occasion.
Early in the spring of 1863, appeared in Böttger’s ‘Polytechnisches
Notizblatt’ (No. 6 of that year) an article which contains in condensed
form Böttger’s discourse. This article was copied into Dingler’s
‘Polytechnisches Journal’ for May 1863. vol. clxviii. p. 185, and also
into the ‘Polytechnisches Centralblatt’ for July 1863, vol. xxix. p.
858. An extract of Reis’s own paper, condensed from the ‘Jahresbericht’
by Dr. Roeber (now President of the Physical Society of Berlin),
appeared in the ‘Berliner Berichte’ (_i. e._ the ‘Fortschritte der
Physik’) for 1861, vol. xvii. pp. 171-173. It is interesting to note
that Reis’s paper was then deemed worthy to stand in the pages of the
‘Fortschritte’ by the side of the classic researches of Thomson on
Regelation, and of Maxwell on Magnetic Lines of Force. The following is
a translation of Böttger’s notice mentioned above.]
[=2.=] ON THE TRANSMISSION OF TONES TO A DISTANCE AS FAR AS DESIRED, BY
THE HELP OF ELECTRICITY (TELEPHONY).
[Translated from the original notice by Professor Böttger,
which appeared in Böttger’s ‘Polytechnischen Notizblatt,’
1863, No. 6, p. 81, in Dingler’s ‘Polytechnisches Journal,’
1863, vol. clxviii. p. 185, and in the ‘Polytechnisches
Centralblatt,’ 1863, t. xxix. p. 858.]
Two decades ago we had not yet gone beyond the first attempts to give
signals at a great distance by the aid of electricity. Since then
telegraphy has attained such a completeness, and the telegraph wire has
reached such a universal extension, that there seems little left for
even the boldest wish to desire.
Now there crops up a first serious research to reproduce tones at any
desired distance by the aid of electricity. This first experiment which
has been crowned with some success, has been made by the teacher of
Natural Science at Friedrichsdorf, not far from Frankfort-on-the-Main,
Herr Ph. Reis, and has been repeated in the Auditorium of the Physical
Society in Frankfort, before numerous assembled members on the 26th
of October, 1861. He caused melodies to be sung not very loudly
into one part of his apparatus, which was placed in a building (the
Bürger-Hospital), about 300 feet distant, with closed windows and
doors. These same melodies were _audible_ to the members in the
meeting-hall by means of the second part of the apparatus. These
wonderful results were attained with the following simple pieces of
apparatus. A little light box, a sort of hollow cube of wood, has a
large opening at its front side, and a small one at the back on the
opposite side. The latter is closed with a very fine membrane (of pig’s
smaller-intestine) which is strained stiff. A narrow springy strip
of platinum foil, fixed at its outer part to the wood, touches the
membrane at its middle; a second platinum strip is fastened by one of
its ends to the wood at another spot, and bears at its other end a fine
horizontal spike, which touches the other little platinum strip where
it lies upon the membrane.
As is known, tones arise from rarefactions and condensations of the air
following quickly after one another. If these motions of the air, known
as waves, strike upon the thin membrane, they press it against the
little plate of platinum with which it is in contact, and immediately
let it vibrate back again into the hollow cube (or so-called artificial
ear): they act so that the membrane now takes a form hollowed toward
the cube, now bulged toward the outside. The little plate of platinum
touching it thereby acquires a vibrating motion, so that it now is
pressed against the spike of the second [platinum plate], now leaves
the same.
If now one little plate of platinum be united by a wire with one pole
of a voltaic battery, and the electricity be led, by a wire fastened to
the other pole of the battery, to any desired distance; there carried
through a spiral, about six inches long, made of a six-fold winding of
very thin covered copper wire; thence led back to the second platinum
strip on the wooden cube through a second insulated wire; then at every
vibration of the membrane an interruption in the current of electricity
takes place because the platinum point no longer touches the other
little strip of platinum. Through the hollow of the wire-spiral there
is stuck a thin iron wire (a strong knitting-needle), which is ten
inches long, and which rests upon two bridges of a sounding-board by
its ends which project on both sides about two inches out of the spiral.
It is known[21] that if an electric current be led through a spiral
which surrounds an iron rod in the manner described, at every
interruption of the same a tone is audible arising from the vibration
of the rod. If the closings and interruptions of the circuit follow
one another relatively slowly, then there is produced by the changes
of position of the molecules of the rod, evoked by the electricity, a
tone,--the so-called longitudinal tone of the rod,--which is dependent
upon the length and stoutness of the rod. But if the closings and
interruptions of the electric current in the spiral follow one another
more rapidly than the vibrations of the smallest particles of the
iron rod,[22] which vibrations are determined by its elasticity, then
these particles cannot complete their paths, receive new impacts,
their vibrations become smaller, but quicker, and follow one another
as frequently as the interruptions. The iron rod then no longer gives
its longitudinal tone, but a tone, which is higher according as the
interruptions are more frequent in the given time, or lower, as they
are less frequent. It is known that the height and depth of tones
depends only on the number of air-waves which follow one another in a
second. We have seen above that by this is determined the number of
interruptions of the electric current of our apparatus by means of the
membrane and the platinum strip. The iron wire must therefore give out
the tone in the same height or depth as that which struck the membrane.
Now since a very far leading of the electricity makes it suffer
scarcely any weakening in proper apparatus, it is intelligible that one
can make the tone which acts on the membrane at one place audible, by
means of the iron rod, at any desired distance.
That the tone is made audible at a distance by the electric
agitations, and not by direct conduction of the sound-waves through the
wires is proved in the most evident way of all, because one instantly
hears no more the tone through the spiral when a good short circuit is
made, as, for example, by laying upon the two wires which conduct the
electricity a strip of sheet metal right in front of the spiral.
The reproduced tones are, of course, somewhat weaker than the original
ones, but the number of vibrations is similar. If thus the reproduction
[of tones] in exactly similar height and depth is easily attained, it
is however difficult for our ear, amidst the always smaller vibrations,
to which the diminished strength of the tone is due, to evaluate
exactly the magnitude of the vibrations. But the character of the tone
depends upon the number of variations of amplitude (Anschwellungen),
that is to say, depends upon whether, for example, in the tones which
have similar pitch and therefore a similar number of waves per second,
the fourth, sixth, eighth, tenth, or sixteenth wave is stronger than
the others. For physicists have shown that an elastic spring is set
in vibration by the thrust of the teeth of a cog-wheel; the first
vibration is the greatest, all those that follow being less. If there
comes, before the spring comes to rest, a fresh thrust from a cog,
then the next vibration is again equal to the greatest first vibration
without the spring making any more vibrations on that account; and by
this means vowel-tones may be artificially produced.
One may also be yet far removed from being able to carry on a
conversation with a friend dwelling a hundred miles distant, and
recognise his voice, as if he sat near us; but it can no longer be
maintained that this is impossible. Indeed the probability that this
will be attained[23] is already become as great as the probability of
the reproduction of natural colours in photography has become through
the notable researches of Niepce.
* * * * *
[The second public exhibition which Reis made of the telephone was,
like the first, in Frankfort-on-the-Main, but this time before a
Society known as the _Freies Deutsches Hochstift_, or Free German
Institute, a kind of Athenæum Club for the city of Frankfort, now for
many years established in the well-known house where the poet Goethe
was born, in the Grosse Hirschgraben. In 1862, however, the Free
German Institute held its meetings in another building known as the
Saalbau. And on May the 11th of that year Philipp Reis lectured upon
and exhibited the Telephone. A journal which appeared then, and still
appears, in Frankfort, with the title of ‘Didaskalia,’ devoted to light
literary and artistic news, popular science, and general intelligence
of an informing character, ordinarily inserted notices of the chief
meetings of the Hochstift. On this occasion a preliminary paragraph was
inserted in the following terms:--]
[=3.=] TELEPHONY, _i.e._ SOUND-TRANSMISSION.
[TRANSLATION FROM ‘DIDASKALIA,’ MAY 8TH, 1862.]
The excellent physicist, Mr. Phil. Reis, of Friedrichsdorf, calls
by this name his surprising invention for using the telegraph line
to transmit really audible tones. Our readers will perhaps remember
having heard some time since of this invention, the first trials with
which Mr. Reis performed here in the Physical Society. Since then the
invention has been constantly developed, and will, no doubt, become of
great importance.
[The lecture which followed this announcement was duly given on the
11th of May. In the Saalbau there is a suite of four rooms. The
Lecture to the assembled members of the Hochstift was delivered in the
Auditorium, at one end of the suite: the wires were passed through the
two intervening rooms to the fourth chamber, where the transmitter was
placed, the doors being closed. The battery and wires were borrowed
from the Physical Society for this occasion, permission for their use
having been granted on May 2nd, as appears in a formal entry in the
minute-book. The following notice of Reis’s discourse, believed to
have been written by Dr. Volger, Founder and first President of the
Hochstift, appeared in ‘Didaskalia’ for May 14th.]
[=4.=] TRANSLATION FROM ‘DIDASKALIA,’ 12TH MAY, 1862.
Yesterday’s meeting of the Free German Institute was a very numerously
attended one from the fact that the subject in the order of business,
“Telephony by Transmission of the Galvanic Current,” as explained by
the inventor himself, Mr. Phil. Reis, excites so great an interest that
it rightly deserves the most general attention.
In a lecture exceedingly interesting, universally understood, clear,
and concise, Mr. Reis gave a historical outline of the origin
and development of his idea of the practical possibility of the
transmission of tones in a galvanic way.
His first attempts were mostly unsuccessful in solving the cardinal
question propounded by him. “How is it possible that a single
instrument can reproduce at once the total action of all the organs
operated in human speech?” Until finally it occurred to him to seek
the solution of the problem in the question, “How does our ear take
cognisance of the total vibrations of all the organs of speech acting
at once?” or “How do we perceive the vibrations of several bodies
sounding at once?”
In order to answer this question the lecturer went more closely into
the anatomy of the ear and into the formation of tones in general.
After this was determined, he took up again his experiments in
reference to the transmission of tones by means of galvanism.
Afterwards Mr. Reis constructed considerably enlarged the parts of the
ear necessary for hearing, by which it was finally possible for him to
transmit the tones brought to the mechanically-imitated ear.
The experiments by him some months ago in the Physical Society, were,
to the astonishment of all, exceedingly plain and clear, whereas the
experiment following the lecture of yesterday was less successful. This
was due partly to the poor conductivity of the wires, partly to the
locality.
Although much is still left to be done for the practical utilisation
(Verwerthung) of the telephone, yet a new and interesting field of
labour is hereby opened to physics.
[No more complete report than the foregoing is to be found, and it is
believed that the discourse, which like all those given by Reis was
delivered extempore, was never committed to writing. Its resemblance to
the discourse of the preceding autumn before the Physical Society is
great; and indeed it may be said that all Reis’s discourses upon the
telephone were practically identical in their contents. A few months
after this lecture, Reis presented a pair of instruments, transmitter
and receiver, to the Hochstift. These instruments were not the same as
those used by Reis at his lecture, but were of the “improved” type,
whilst those used by Reis at his lecture to the Hochstift, were, so far
as respects the transmitter at least, more like the form described by
W. von Legat, and figured in Plate II., Fig. A;[24] and according to
Mr. Horkheimer, who helped Reis on this occasion, the transmitter was
provided with a conical mouthpiece of wood. The transmitter presented
later by Reis is of the “square-box” form (Fig. 17), and is stamped,
“1863, Philipp Reis, 2,” and the receiver is of the “knitting-needle”
form (Fig. 23). These instruments are carefully preserved by the
Hochstift in the “Goethehaus,” amongst their archives “in everlasting
remembrance” of the inventor. A few months later, in 1863, the Emperor
of Austria and the late king Max of Bavaria were residing at Frankfurt
and visited the “Goethehaus;” and on this occasion Reis’s instruments
were shown to these distinguished visitors by the Founder and President
of the Hochstift, Dr. Volger.
In honour of his brilliant invention Reis was, shortly after his
lecture, elected an honorary member of the Freies Deutsches Hochstift.]
* * * * *
[The next document in order is a Report by Wilhelm von Legat,
communicated to the Austro-German Telegraph Union (Verein) in 1862, and
printed in the ‘Journal’ of that Society. It was reprinted verbatim
in Dingler’s ‘Polytechnisches Journal,’ for 1863, vol. clxix. p. 29.
This Report is of great importance. It is quoted by Graham Bell, in
his earliest account of _his_ telephone. It was this Report, moreover,
which in 1875 or 1876, in a translated manuscript form, was put into
Mr. Edison’s hands by the then President of the Western Union Telegraph
Company, and which formed the starting-point of Edison’s subsequent
work.]
[=5.=] ON THE REPRODUCTION OF TONES IN THE ELECTRO-GALVANIC WAY.
By V. LEGAT, Inspector of the Royal Prussian Telegraphs in Cassel.
[Translated from the Journal of the Austro-German Telegraph
Society (edited by Dr. Brix), vol. ix. p. 125, 1862.
(Zeitschrift des deutschösterreichischen Telegraphen-Vereins,
1862.)]
It might not be uninteresting to make known to wider circles
the following ideas concerning the reproduction of tones in an
electro-galvanic way, which have recently been put forward by Herr
Philipp Reiss [_sic_] of Friedrichsdorf, before the Physical Society,
and before the meetings of the Free German Institute (Freies Deutsches
Hochstift) in Frankfort-on-the-Main; also to state what has hitherto
been attained in the realisation of this project, in order that
building upon the collected experiences and the efficacy of the
galvanic current, what has already been made serviceable to the human
intellect for the advancement of its correspondence, may in this
respect also be turned to profit.
In what is here announced we are concerned not with the action of
the galvanic current in moving telegraphic apparatus of whatever
construction for producing _visible_ signals, but with its application
for the production of _audible_ signals--of _tones_!
The air-waves, which by their action within our ears awaken in us
the sensation of sound, by first of all setting the drum-skin into
a vibrating motion, are thence, as is known, conveyed to the inner
part of the ear and to the auditory nerves lying there by a lever
apparatus of the most marvellous fineness,--the auditory ossicles
(including “Hammer,” “Anvil,” and “Stirrup”). The experiment for the
reproduction of tones is based upon the following: viz. to employ an
artificial imitation of this lever-apparatus and to set it in motion by
the vibrations of a membrane like the drum-skin in the ear, and thus
to open and close a galvanic circuit which is united by a metallic
conductor with a distant station.
Before the description of the necessary apparatus is followed out,
it might be necessary, however, to go back to the point how our ear
perceives the vibrations of a given tone, and the total vibrations of
all the tones simultaneously acting upon it; because by this means will
be determined the various requisite conditions which must be fulfilled
by the transmitting and receiving apparatus for the solution of the
problem that has been set.
Let us consider first the processes which take place in order that a
single tone should be perceived by the human ear; so shall we find that
each tone is the result of a condensation and rarefaction several times
repeated in a certain period of time. If this process is going on in
the same medium (the air) in which our ear is situated, the membrane
will at every condensation be forced toward the hollow of the drum, and
at every rarefaction will move itself in the opposite direction.
These vibrations necessitate a similar motion of the auditory ossicles,
and thereby a transference to the auditory nerves is effected.
The greater the condensation of a sound-conducting medium at any given
moment, the greater also will be the amplitude of vibration of the
membrane and of the auditory ossicles and of their action; and in the
converse case the action will be proportionally less. It is, therefore,
the function of the organs of hearing to communicate with fidelity to
the auditory nerves every condensation and rarefaction occurring in
the surrounding medium; whilst it remains to be the function of the
auditory nerves to bring to our consciousness the number as well as
the magnitude of the vibrations ensuing in a given time.
Here in our consciousness a definite name is given to a certain
composition, and here the vibrations brought to the consciousness
become “tones.”
That which is perceived by our auditory nerves is consequently the
effect upon our consciousness of a force which, according to its
duration and magnitude, may for the sake of better comprehension, be
exhibited graphically.
[Illustration]
Let, for example, the length of the line _a b_ be any definite duration
of time, and let the curves above this line denote the condensations
(+), and the curves below this line the rarefactions (-); then every
ordinate erected at the extremity of an abscissa gives us the strength
of the condensation in consequence of which the drum-skin vibrates, at
the moment indicated by the position of the foot of the ordinate.
Anything more than that which is exhibited in this way or by similar
curves our ear cannot in the least perceive, and this is sufficient to
bring to our consciousness each single tone and each given combination
of tones. For, if several tones are produced at the same time,
the sound-conducting medium is put under the influence of several
simultaneously acting forces which are subject to the laws of mechanics.
If all the forces operate in the same sense, then the magnitude of the
motion is proportional to the sum of the forces. If the forces act in
opposite directions, the magnitude of the motion is proportional to the
difference between the opposing forces.
Consequently it is possible out of the condensation-curves of several
simultaneously-occurring tones to compound, by the foregoing
principles, a condensation-curve which exactly expresses that which our
ear experiences on the reception of these simultaneously-acting tones.
The objection ordinarily made to this, that a musician, or even any
one, is able to hear separately the single tones of which this combined
curve is built and constructed, cannot be admitted as a proof to the
contrary; for one expert in the science of colour will, for example,
in the same way discern in green a mixture of yellow and blue in their
various shades: and the one phenomenon equally with the other may be
referred back to this; that, to the person concerned, the factors which
make up the product of that which reaches his consciousness are well
known.
According to that which has been already explained, it is easy to
construct the condensation-curves of various tones, chords, &c., and
for the sake of clearness some examples follow:--
Fig. 1, Plate I.,[25] shows a combination curve of three tones, in
which all the proportions of the components recur successively.
Fig. 2 shows such a curve of more than three tones, in which the
proportions in the drawing can no longer so evidently be given; yet
the practised musician would here recognise them, even although in
practice it might be difficult for him to single out, in such chords,
the separate tones.
This method of exhibiting the action of tones upon the human ear offers
the advantage of a very clear perception of the process; and that which
is exhibited (Fig. 3) shows also why a discord must affect our ear
unpleasantly.
This apparent digression from the aim set forth was necessary in
order to indicate that as soon as it is possible for us to create
anywhere, and in any manner whatever, vibrations whose curves and
magnitudes are similar to the vibrations of any given tone, or of any
given combination of tones, we shall have the same impression as this
original tone or this original combination of tones would have produced
upon us.
The apparatus hereafter described offers the possibility of creating
these vibrations in every fashion that may be desired, and the
employment of electro-galvanism gives us the possibility of calling
into life, at any given distance, vibrations similar to the vibrations
that have been produced, and in this way to reproduce at any place the
tones that have been originated at another place.
In Fig. 4, Plate II.,[26] herewith presented, A is the transmitter
(Tonabgeber), and B the receiver (Tonempfänger), which two instruments
are set up at different stations. I make, however, the preliminary
remark that the manner of joining the instruments for interchangeable
use backward and forward is here omitted for the sake of clearness,
and the more so because the whole is not here propounded as a final
fact, but in order to bring that which has been hitherto accomplished
to the knowledge of a wider circle. The possibility of the working of
the apparatus to a greater distance than that which at present limits
in practice the direct working of the galvanic current may also be
left out of consideration, since these points may be easily rendered
possible by mechanical precautions, and do not affect the essential
part of the phenomena now described.
Let us next turn to the transmitter, Fig. A. It is put into
communication on one side with the metallic conductor leading to the
neighbouring station, and by means of this with the receiver, Fig.
B; on the other side it is connected, by means of the electro-motive
power, C, with the earth or a metallic return-conductor.
The transmitter, Fig. A, consists of a conical tube, _a b_, of about
15 centimetres length, 10 centimetres in the front, and 4 centimetres
in the back aperture.
(In the practical investigations it has been established that the
choice of material for this tube is without influence on the use of the
apparatus, and moreover a greater length of the same for the certainty
[of action] of the apparatus is without effect. A greater width of the
cylinder spoils the usefulness of the apparatus; and it is recommended
that the interior surface be as smooth as possible.)
The narrow hinder aperture of the cylinder is closed by a membrane,
_o_, of collodion, and on the middle of the circular surface formed
by this membrane rests one end, _c_, of the lever, _c d_, the fulcrum
(point of support), _c_, of which, supported on a bearing, remains
joined to the metallic conductor.
The choice of the length of the two arms of the lever, _c e_ and _e d_,
is determined by the laws of force of levers. It is recommended that
the arm, _c e_, be constructed longer than the arm _e d_, in order to
bring the smallest movement at _c_ into action at _d_ with the greatest
possible force; but, on the other hand, it is desirable to make the
lever itself as light as possible, in order that it may follow the
motions of the membrane. An uncertain following of the lever, _c d_,
produces impure tones at the receiving station. In the condition of
rest the contact, _d g_, is closed, and a delicate spring, _n_, holds
the lever firmly in this position of rest.
The second part of this apparatus, the pillar, _f_, consists of a
metallic support, which is united with one pole of the battery, C,
while the second pole of the battery is carried to the metallic
conductor of the other station.
Upon the support, _f_, there is a spring, _g_, with a contact, which
corresponds to the contact at _d_ of the lever _c d_, and whose
position is regulated by a screw, _h_.
In order not to weaken the action of the apparatus by the
communication of the air-waves which are produced in using the
apparatus, against the back of the membrane, it is recommended, in
using the apparatus, to place over the tube, _a b_, at right angles to
its longitudinal axis, a screen of about 50 centimetres diameter, which
fixes tight upon the outer surface of the tube.
The receiver, Fig. B, consists of an electro-magnet, _m m_, which
reposes upon a sounding-box, _u w_, and whose wire coils are
respectively connected with the metallic conductor and with the earth
or metallic return-conductor.
Opposite the electro-magnet, _m m_, stands an armature, which is
connected with a lever, _i_, which is long as possible, but light and
broad.
The lever, _i_, is fastened, pendulum-wise, to the support, _k_, and
its movements are regulated by the screw, _l_, and the spring, _p_.
In order to improve the action of the apparatus, this receiver can be
placed in one focus of an elliptically arched cavity of corresponding
size, in which case, then, the ear of him who is listening to the
reproduced tones may be placed at the second focus of this cavity.
The action of the two apparatuses here described, is the following:--
In a condition of rest the galvanic circuit is closed.
In the apparatus, Fig. A, by speaking (singing, or leading into it the
tones of an instrument) into the tube _a b_, in consequence of the
condensation and rarefaction of the air present in this tube, there
will be evoked a motion of the membrane closing the tube at its narrow
end, corresponding to this condensation or rarefaction. The lever,
_c d_, follows the motion of the membrane, and opens and closes the
galvanic circuit at _d g_, so that by each condensation of the air in
the tube an opening, and at each rarefaction a closing of the galvanic
circuit ensues.
In consequence of this process, the electro-magnet of Fig. B (the
receiver) will be demagnetised and magnetised correspondingly with the
condensations and rarefactions of the mass of air in the tube A, _a b_
[the mouth-piece of the transmitter], and the armature belonging to the
magnet will be set into vibrations similar to those of the membrane
in the transmitting apparatus. The plank, _i_, connected with the
armature, conveys these similar vibrations to the air surrounding the
apparatus, Fig. B, which finally transmits to the ear of the listener
the tones thus produced.
We are not, therefore, dealing here with a propagation of sound through
the electric current, but only with a transference to another place of
the tones that have been produced, by a like cause being brought into
play at this second place, and a like effect produced.
Here, however, it must not be overlooked that the preceding apparatus
reproduces, indeed, the original vibrations in equal number, but that
equal strength in the reproduced vibrations has not yet been attained,
and the production of these is reserved for a completion of the
apparatus.
One consequence of this temporary incompleteness of the apparatus,
is that the slighter differences of the original vibrations are more
difficult to discern: that is to say, the vowel appears more or less
indistinct, the more so since each tone is dependent, not only on the
number of vibrations of the medium, but also on the condensation or
rarefaction of the same.
By this it is also explained, that, in the practical investigations
heretofore carried on, chords, melodies, etc., were transmitted
with marvellous fidelity; while single words uttered as in reading,
speaking, and the like, were perceptible more indistinctly.
Nevertheless, here also the inflexions of the voice, the modulations
of interrogation, exclamation, wonder, command, &c., attained distinct
expression.
There remains no doubt, that before expecting a practical utilisation
with serviceable results (praktische Verwerthung mit Nutzen), that
which has been here spoken of will require still considerable
improvement, and in particular mechanical science must complete
the apparatus to be used; yet I am convinced by repeated practical
experiments that the prosecution of the subject here explained is of
the highest theoretical interest, and that our intelligent century will
not miss the practical utilisation (Verwerthung) of it.
* * * * *
[This article was also reprinted verbatim in Dingler’s Polytechnisches
Journal, vol. clxix. p. 29, 1863.]
* * * * *
[A peculiar interest is attached to the foregoing article, partly on
account of the unique nature of the instruments therein described,
partly because of the mystery attaching to the author of the article.
Wilhelm von Legat was Inspector of the Royal Prussian Telegraphs
at Cassel. How or when he became acquainted with Philipp Reis is
not known--possibly whilst the latter was performing his year of
military service at Cassel in 1855. None of Reis’s intimate friends
or colleagues now surviving can give any information as to the nature
of von Legat’s relations with Reis, as not even his name is known to
them, save from this Report. Yet he was for one year only (1862), the
year in which this Report was made, a member of the Physical Society
of Frankfort-on-the-Main. It is possible that he may have been present
at Reis’s discourse in the preceding October. It is probable that he
was present at Reis’s subsequent discourse in May, 1862, to the Freies
Deutsches Hochstift. Dr. Brix, then editor of the ‘Journal of the
Telegraph Union,’ informs me that Inspector von Legat based his article
upon information derived direct from Reis, whom he knew, and that the
article was submitted to Reis before being committed to the ‘Journal.’
The particular form of transmitter described in von Legat’s Report
(see also p. 25, _ante_) has also some important points in common with
that believed to have been used by Reis at the Hochstift. Neither of
the specific forms described by Inspector von Legat are now known to
be extant. Inquiries made in Frankfort and in Cassel have failed to
find any trace of them. Neither at the local Naturalists’ Society, nor
anywhere else in Cassel, did von Legat describe the invention. He met
with a tragic end during the Bavarian War in 1866, in the battle near
Aschaffenburg, having, according to some, been shot, or, according to
others, fallen from his horse.]
* * * * *
[The next extract is from an article entitled ‘Telephonie,’ which
appeared in a journal of science published at Leipzig, under the title
‘Aus der Natur.’ This article is essentially a paraphrase of Reis’s
memoir read to the Physical Society in the preceding December (see
p. 50), and contains the same illustrations, including a cut of the
transmitter identical with Fig. 9, p. 20.]
[=6.=] AUS DER NATUR. (Vol. xxi. 1862. July-October. pp. 470-474.)
“Until now, however, it was not possible to reproduce human speech with
a distinctness sufficient for every person. The consonants are mostly
tolerably distinctly reproduced, but the vowels not in an equal degree.”
* * * * *
[About this time there arose a Correspondence in the ‘Deutsche
Industrie Zeitung’ (‘German Journal of Industry’) concerning the
telephone. In No. xvi. p. 184 (1863), a correspondent who signs himself
“K” asks whether the account of the telephone is true? In No. xviii.
p. 208, there is given a brief answer; and No. xxii. contains, on p.
239, an extract from Legat’s Report, on Reis’s Telephone (see p. 70 of
this work), together with an editorial remark to the effect that he had
received a letter from Herr J. F. Quilling, of Frankfort-on-the-Main,
who gives the information that in the transmission of singing in the
telephone, the singer could be recognized by his voice.]
[=7.=] [EXTRACT FROM THE ANNUAL REPORT OF THE PHYSICAL SOCIETY OF
FRANKFORT-ON-THE-MAIN (1863).]
...; “and on the 4th of July, 1863, by Mr. Philipp Reis, teacher, of
Friedrichsdorf, _On the Transmission of Tones to any desired Distance,
by the help of Electricity, with the production of an Improved
Telephone, and Exhibition of Experiments therewith_.”
[This was Reis’s second occasion of bringing his Telephone before the
Physical Society. The instrument had now-assumed the “square-box”
pattern described at p. 27 of this work.]
[=8.=] LETTER OF PHILIPP REIS.
[In July 1863, Mr. W. Ladd, the well-known instrument-maker of London,
bought one of Reis’s Telephones of Messrs. J. W. Albert and Son of
Frankfort. Philipp Reis wrote to Mr. Ladd the following letter of
instructions, having heard that Mr. Ladd proposed to exhibit the
instrument at the approaching meeting of the British Association. The
autograph letter, written in English, is still preserved, and has been
presented by Mr. Ladd to the Society of Telegraph Engineers and of
Electricians of London.]
“Institut Garnier,
“Friedrichsdorf.
“Dear Sir!
“I am very sorry not to have been in Francfort when you were
there at Mr. Albert’s, by whom I have been informed that
you have purchased one of my newly-invented instruments
(Telephons). Though I will do all in my power to give you the
most ample explanations on the subject, I am sure that personal
communication would have been preferable; specially as I was
told, that you will show the apparatus at your next sientifical
meeting and thus introduce the apparatus in your country.
“Tunes[27] and sounds of any kind are only brought to our
conception by the condensations and rarefactions of air or
any other medium in which we may find ourselves. By every
condensation the tympanum of our ear is pressed inwards, by
every rarefaction it is pressed outward and thus the tympanum
performs oscillations like a pendulum. The smaller or greater
number of the oscillations made in a second gives us by help of
the small bones in our ear and the auditory nerve the idea of a
higher or lower tune.
“It was no hard labour, either to imagine that any other
membrane besides that of our ear, could be brought to make
similar oscillations, if spanned in a proper manner and if
taken in good proportions, or to make use of these oscillations
for the interruption of a galvanic current.
“However these were the principles wich (_sic_) guided me
in my invention. They were sufficient to induce me to try
the reproduction of tunes [_i.e._, tones--see footnote.--S.
P. T.] at any distance. It would be long to relate all the
fruitless attempts, I made, until I found out the proportions
of the instrument and the necessary tension of the membrane.
The apparatus you have bought, is now, what may be found most
simple, and works without failling when arranged carefully in
the following manner.
“The apparatus consists of two separated parts; one for the
singing station A, and the other for the hearing station B.[28]
[Illustration: Fig 28.]
“The apparatus A, a square box of wood, the cover of which
shows the membrane (_c_) on the outside, under glass. In the
middle of the latter is fixed a small platina plate to which
a flattened copper wire is soldered on purpose to conduct the
galvanic current. Within the cercle you will further remark
two screws. One of them is terminated by a little pit in which
you put a little drop of quiksilver; the other is pointed. The
angle, which you find lying on the membrane, is to be placed
according to the letters, with the little whole [hole] (_a_)
on the point (_a_) the little platina foot (_b_) into the
quicksilver screw, the other platina foot will then come on the
platina plate in the middle of the membrane.
“The galvanic current coming from the battery (which I compose
generally of three or four good elements) is introduced at
the conducting screw near (_b_) wherefrom it proceeds to the
quicksilver, the movable angle, the platina plate and the
complementary telegraph to[29] the conducting screw (_s_). From
here it goes through the conducter to the other station B and
from there returns to the battery.
“The apparatus B, a sonorous box on the cover of which is
placed the wire-spiral with the steel axis, wich will be
magnetic when the current goes through the spiral. A second
little box is fixed on the first one, and laid down on the
steel axis to increase the intensity of the reproduced
sounds. On the small side of the lower box you will find the
correspondent part of the complementary telegraph.
“If a person sing at the station A, in the tube (_x_) the
vibrations of air will pass into the box and move the
membrane above; thereby the platina foot (_c_) of the movable
angle will be lifted up and will thus open the stream at
every condensation of air in the box. The stream will be
re-established at every rarefaction. For this manner the
steel axis at station B will be magnetic once for every full
vibration; and as magnetism never enters nor leaves a metal
without disturbing the equilibrium of the atoms, the steel-axis
at station B must repeat the vibrations at station A and thus
reproduce the sounds which caused them.
“_Any_[30] sound will be reproduced, if strong enough to set
the membrane in motion.
“The little telegraph, which you will find on the side of the
apparatus is very usefull and agreable for to give signals
between both of the correspondents. At every opening of the
stream and next following shutting the station A will hear a
little clap produced by the attraction of the steel spring.
Another little clap will be heard at station (B) in the
wire-spiral. By multiplying the claps and producing them in
different measures you will be able as well as I am to get
understood by your correspondent.
“I am to end, Sir, and I hope, that what I said will be
sufficient to have a first try; afterward you will get on quite
alone.
“I am, Sir,
“Your most obediant Servant,
“Ph. Reis.
“Friedrichsdorf, 13/7, 63.”
[=9.=] REIS’S PROSPECTUS.
[The following “Prospectus” of instructions was drawn up by Reis to
accompany the Telephones which were sold by Herr Wilh. Albert of
Frankfort. The author of this book is in possession of original copies,
of which a number are extant. The “Prospectus” was also reprinted
in its entirety at page 241 of Professor Pisko’s book ‘Die neueren
Apparate der Akustik,’ published at Vienna in 1865.]
TELEPHON.
Each apparatus consists, as is seen from the above illustration, of
two parts: the Telephone proper, A, and the Reproduction apparatus
[Receiver], C. These two parts are placed at such a distance from each
other, that singing, or the tones of a musical instrument, can be heard
from one station to the other in no way except through the apparatus
itself.
Both parts are connected with each other, and with the battery, B,
like ordinary telegraphs. The battery must be capable of effecting the
attraction of the armature of the electromagnet placed at the side of
station A (3-4 six-inch Bunsen’s elements suffice for several hundred
feet distance).
The galvanic current goes then from B to the screw, _d_, thence through
the copper strip to the little platinum plate at the middle of the
membrane, then through the foot, _c_, of the angular piece to the
screw, _b_, _in whose little concavity a drop of quicksilver is put_.
From here the current then goes through the little telegraph apparatus,
_e-f_, then to the key of station C, and through the spiral past _i_
back to B.
[Illustration: Fig. 29.]
If now sufficiently strong tones are produced before the
sound-aperture, S, the membrane and the angle-shaped little hammer
lying upon it are set in motion by the vibrations; the circuit will
be once opened and again closed for each full vibration, and thereby
there will be produced in the iron wire of the spiral at station C
the same number of vibrations which there are perceived as a tone
or combination of tones (chord). By imposing the little upper case
(Oberkästchen) firmly upon the axis of the spiral the tones at C are
greatly strengthened.
Besides the human voice (according to my experience) there also can
be reproduced the tones of good organ-pipes from F--c' and those of a
piano. For the latter purpose A is placed upon the sounding-board of
the piano. (Of thirteen triads (Dreiklänge) a skilled experimentor
could with all exactness recognise ten).
As regards the telegraph apparatus placed at the side, it is clearly
unnecessary for the reproduction of tones, but it forms a very
agreeable addition for convenient experimenting. By means of the same,
it is possible to make oneself understood right well and certainly by
the other party. This takes place somewhat in the following manner:
After the apparatus has been completely arranged, one convinces oneself
of the completeness of the connexion and the strength of the battery
by opening and closing the circuit, whereby at A the stroke of the
armature is heard, and at C a very distinct ticking.
By rapid alternate opening and closing at A it is asked at C whether
one is ready for experimenting, whereupon C answers in the same manner.
Simple signals can by agreement be given from both stations by opening
and closing the circuit one, two, three, or four times; for example:--
1 beat = Sing.
2 beats = Speak, &c.
I telegraph the words thus--that I number the letters of the alphabet
and then transmit their numbers--
1 beat = _a_.
2 beats = _b_.
3 " = _c_.
4 " = _d_.
5 " = _e_, &c.
_z_ would accordingly be designated by twenty-five beats.
This number of beats would, however, appear wasteful of time, and would
be uncertain in counting, wherefore I employ for every five beats a
dactyl-beat (Dactylusschlag), and there results
[Illustration:--~ ~] for _e_.
[Illustration:--~ ~] and one beat for _f_, &c.
_z_, = [Illustration:--~ ~,--~ ~,--~ ~,--~ ~,--~ ~] which is more
quickly and easily executed and easier to understand.
It is still better if the letters are represented by numbers which are
in inverse proportion to the frequency of their occurrence.
Phil. Reis,
Teacher at L. F. Garnier’s Institute for boys.
Friedrichsdorf, near Homburg-by-the-Height,
August 1863.
[The foregoing “Prospectus” was accompanied by a further document
printed as a postscript by Reis, at the top of which the figure of the
instrument was repeated, and which ran as follows:--]
“P. P.,
“Since two years ago I succeeded in effecting the possibility
of the reproduction of tones by the galvanic current, and in
setting up a convenient apparatus therefor, the circumstance
has found such a recognition from the most celebrated men of
science, and so many calls to action have come to me, that I
have since striven to improve my originally very incomplete
apparatus, so that the experiments might thereby become
accessible to others.
“I am now in the position to offer an apparatus which fulfils
my expectations, and with which each physicist may succeed in
repeating the interesting experiments concerning reproduction
of tones at distant stations.
“I believe I shall fulfil the wish of many if I undertake to
bring these improved instruments into the possession of the
[physical] cabinets. Since the preparation of the same requires
a complete acquaintance with the leading principles and a
tolerable experience in this matter, I have decided myself to
prepare the most important parts of the same, and to leave the
fashioning of the accessory parts, as also of the external
adornments, to the mechanician.
“The distribution of the same I have made over to Herr J.
Wilh. Albert, mechanician, in Frankfort-on-the-Main, and have
placed him in the position to deliver these instruments in
two qualities, differing only in external adornment, at the
prices of 21 florins and 14 florins (12 thalers and 8 thalers
current), inclusive of packing. Moreover, the instruments can
also be obtained direct from me at the same prices, upon a cash
remittance of the amount.
“Each apparatus will be tested by me before sending off, and
will then be furnished with _my name, an order-number, and with
the year_ of manufacture.
“Friedrichsdorf, near Homburg-by-the-Height,
“in August 1863.
“Phil. Reis,
“Teacher at L. F. Garnier’s Institute for Boys.”
[In September of the same year the telephone was shown by Prof.
R Böttger at the meeting of the German Naturalists’ Association
(Naturforscher), which met on that occasion at Stettin. Little or
nothing is known of what took place at this exhibition, but Professor
von Feilitzsch, of the neighbouring University of Greifswald, has
informed the author of this work that the Telephone there shown was of
the form figured in Reis’s Prospectus (p. 86), and that Reis claimed at
that time to be able to transmit words by his instruments. In the same
autumn the following notice appeared in Böttger’s ‘Notizblatt,’ and was
copied thence into Dingler’s ‘Journal,’ and other scientific papers.]
[=10.=] ON THE IMPROVED TELEPHONE.
[Translated from the original notice which appeared in
Böttger’s ‘Polytechnisches Notizblatt,’ 1863, No. 15, p. 225,
and in Dingler’s ‘Polytechnisches Journal,’ 1863, vol. clxix.
p. 399.]
At the meeting of the Physical Society of Frankfort-on-the-Main,
on the 4th of July, a member of this Society, Herr Ph. Reis, of
Friedrichsdorf, near Homburg-vor-der-Höhe, exhibited some of his
improved Telephones (means for the reproduction of tones at any desired
distance by the galvanic current). It is now two years since Herr Reis
first gave publicity to his apparatus,[31] and though even already at
that time the performances of the same in their simple artless form
were capable of exciting astonishment, yet they had then the great
defect that experimenting with them was only possible to the inventor
himself. The instruments exhibited in the above-named meeting scarcely
reminded one of the earlier ones. Herr Reis has also striven to give
them a form pleasing to the eye, so that they may now occupy a worthy
place in every Physical Cabinet. These new apparatus may now also be
handled by every one with facility, and work with great certainty.
Melodies gently sung at a distance of about 300 feet were repeated by
the instrument which was set up, much more distinctly than previously.
The scale was reproduced especially sharply. The experimenters could
even communicate words to one another, though certainly indeed only
such as had often been heard by them. In order moreover that others who
are less accustomed [to experimenting] may be able to understand one
another through the apparatus, the inventor has placed on the side of
the same a little arrangement,[32] which according to his explanation
is completely sufficient, the speed of communication of which is
indeed not so great as that of modern Telegraphs, but which works
quite certainly, and requires no special skill on the part of the one
experimenting with it.
We would bring to the notice of gentlemen who are professional
physicists that the inventor of these interesting pieces of apparatus
now has them prepared for sale under his oversight (the important parts
he makes himself), and the same can be procured from him direct, or
through the mechanician, Mr. Wilhelm Albert, of Frankfort-on-the-Main,
at 14 and at 21 florins, in two qualities, differing only in external
adornment.
[A review, written by Dr. Röber of Berlin, of this and other articles
relating to the Telephone appeared subsequently in the ‘Fortschritte
der Physik,’ 1863, p. 96.]
[Another consequence of the publicity thus given to the Telephone was
the appearance of an article on that instrument, under the title of
“Der Musiktelegraph,” in a popular illustrated weekly family paper,
‘Die Gartenlaube,’ published at Leipzig. This article, from the pen, it
is believed, of Dr. Oppel of Frankfort, is made up chiefly of slightly
altered extracts from the previously quoted documents. The form of
the instrument described is identical with that described in Reis’s
‘Prospectus,’ and the figure given in the ‘Gartenlaube,’ No. 51, p.
809, is a reprint, apparently from the same wood-block of the figure
which heads Reis’s Prospectus, and which is reproduced on p. 86 of this
work. The only passage of further interest is a brief sentence relating
to the exhibition of the Telephone at the German Naturalists’ Assembly
at Stettin in 1863, and is as follows:--]
[=11.=] “Now in order also to give to a still wider circle, especially
to technologists (Fachmännern), the opportunity of witnessing with
their own eyesight the efficiency of this apparatus,--lately, in fact
essentially improved,--Professor Böttger of Frankfort-on-the-Main
exhibited several experiments therewith at the meeting of the German
Naturalists (Naturforscher) and Physicians recently held at Stettin, in
the Section for Physics; which [experiments] would certainly have been
crowned with still greater success if the place of meeting had been in
a less noisy neighbourhood, and had been filled with a somewhat less
numerous audience.”
[The next extract is a brief record from the Report of a scientific
society meeting in Giessen, which during the Austro-Prussian war of
1866 had become disorganised, and which in 1867 published a condensed
account of its proceedings for the preceding years. Amongst those
proceedings was a lecture by the late Professor Buff, at which Reis’s
Telephone was shown, and at which Reis himself is believed to have been
present.]
[=12.=] [EXTRACT FROM THE ‘TWELFTH REPORT OF THE UPPER-HESSIAN
ASSOCIATION FOR NATURAL AND MEDICAL SCIENCE,’ (‘Oberhessische
Gesellschaft für Natur und Heilkunde,’) Giessen, February 1867.]
P. 155. Report on the doings and condition of the Association from the
1st of July, 1863, to the 1st of July, 1865, by Herr Gymnasiallehrer
Dr. W. Diehl.
... On the 13th of February [1864], ‘On the Tones of the Magnet, with
Application to the Telephone, with experiments,’ by Professor Buff.
EXHIBITION OF THE TELEPHONE TO THE NATURALISTS’ ASSOCIATION OF
GERMANY. (DEUTSCHE NATURFORSCHER VERSAMMLUNG.)
[By far the most important of all the public exhibitions given by
Reis of his Telephone, was that which took place on the 21st of
September, 1864, at Giessen, on the occasion of the meeting of the
German Naturalists’ Association (Versammlung Deutsche Naturforscher).
Here were assembled all the leading scientific men of Germany,
including the following distinguished names, many of whom are still
living:--Prof. Buff (Giessen), Prof. Poggendorff (Berlin), Prof. Bohn
(Frankfurt-a.-M., now of Aschaffenburg), Prof. Jolly (Munich), Dr.
Geissler (Bonn), Prof. Weber (Göttingen), Prof. Plücker (Bonn), Prof.
Quincke (Heidelberg), Prof. Dellmann (Kreutznach), Prof. Böttger
(Frankfurt-a.-M. and Mainz), Prof. Kekule (Bonn), Prof. Gerlach
(Erlangen), Dr. J. Frick (Carlsruhe), Dr. F. Kohlrausch (Würtzburg),
Prof. Reusch (Tübingen), Prof. J. Müller (Freiburg), Prof. Helmholtz
(Heidelberg), Prof. Melde (Marburg), Prof. Kopp (Marburg), Prof. A.
W. Hoffmann (London, now of Berlin), Mons. Hofmann (Paris, optician),
Hofrath Dr. Stein (Frankfurt-a.-M.), Dr. W. Steeg (Homburg), Mons.
Hartnack (Paris, and of Pottsdam), Prof. G. Wiedemann (Basel, now of
Leipzig), E. Albert (Frankfurt-a.-M., mechanician), Dr. Thudichum
(London), W. Schultze (York, apothecary), Dr. J. Barnard Davis
(Shelton), E. J. Chapman (London, chemist), Dr. L. Beck (London,
chemist), Prof. Chas. J. Himes (U.S.A., chemist), E. W. Blake (New
Haven, U.S.A., student), C. G. Wheeler (United States Consul in
Nürnberg), and many others. Dr. C. Bohn (now of Aschaffenburg) was
Secretary of the Association, and also Secretary of the Section of
Physics. The meetings of this Section were held in the Laboratory of
Professor Buff. Reis came over from Friedrichsdorf accompanied by
his young brother-in-law, Philipp Schmidt. A preliminary trial on the
morning of that day was not very successful, but at the afternoon
sitting, when communications were made to the Section by Prof. Buff,
by Reis himself, and by Prof. Poggendorff, the instrument was shown
in action with great success. Reis expounded the story how he came to
think of combining with the electric current interruptor a tympanum
in imitation of that of the human ear, narrating his researches in
an unassuming manner that won his audience completely to him; and
the performance of the instrument was received with great applause.
Various professors essayed to experiment with the instrument, with
varying degrees of success according to whether their voices suited the
instrument or not. Amongst these were Prof. Böttger and Prof. Quincke
of Heidelberg, whose account of the occasion is to be found on p.
112. Dr. Bohn, the Secretary of the Section, wrote for the ‘Journal’
(Tagesblatt), issued daily, the following notice.]
[=13.=] EXTRACT FROM THE REPORT OF THE GERMAN NATURALISTS’ SOCIETY,
HELD AT GIESSEN (1864).
“Afternoon sitting on 21st September, 1864.
“Prof. Buff speaks about the tones of iron and steel rods when
magnetised, and exhibits the corresponding experiments.
“Dr. Reis demonstrates his Telephone, gives thereupon an explanation
and the history of this instrument.
“Prof. Poggendorff produces tones in a metal cylinder, the slit up
edges of which touch one another firmly, and which is placed loosely
round an induction-bobbin through which there goes an interrupted
current.”
[This occasion was the crowning point of Philipp Reis’s career, and
might have proved of even greater importance but for two causes: the
inventor’s precarious health, and the indifference with which the
commercial world of Germany viewed this great invention. Where the
keen insight of Reis contemplated the vast possibilities opened out
by the invention of a new mode of inter-communication, others saw only
an ingenious philosophical toy, or at best a pleasing illustration
of certain known principles of acoustic and electric science. And in
spite of the momentary enthusiasm which the exhibition of the Telephone
had evoked, the interest in it dwindled away. A few of the public
journals of that date, noticed the invention in eulogistic terms and
spoke of the prospect it afforded of communication between distant
friends and of simultaneous concerts being given in different towns,
all transmitted telephonically from one orchestra. But the invention
came too early. The public mind was not yet prepared to take it up,
and the enthusiasm died away. Still in a few of the more important
books on Physics, Acoustics, and Electricity, the matter continued to
receive attention. In the well-known Müller-Pouillet’s ‘Textbook of
Physics’ (Lehrbuch der Physik) edited by Professor J. Müller; in the
‘Technical Physics’ of Hessler, of Vienna, edited by Professor Pisko;
in Pisko’s ‘Recent Apparatus of Acoustics,’ and particularly in Kuhn’s
admirable ‘Handbook of Applied Electricity,’ the Telephone was accepted
as a definite conquest of science, and was described and figured. From
the works named we transcribe the extracts which follow, and which
sufficiently explain themselves.]
[=14.=] EXTRACT FROM MÜLLER-POUILLET’S ‘TEXTBOOK OF PHYSICS AND
METEOROLOGY’ (LEHRBUCH DER PHYSIK UND METEOROLOGIE).
[Published at Brunswick, Sixth ed., 1863, vol. ii. page 352, fig. 325;
and Seventh ed., 1868, vol. ii. pages 386-388, figs. 348-350. The
following translation is from the latter edition.]
“This tone ... has Reis used for the construction of his Telephone.
“Figure 348[33] exhibits Reis’s interrupting apparatus. In the lid of
a hollow cube of wood A, a circular opening is made, which is closed
by an elastic membrane (pig’s lesser intestine) strained over it. Upon
the centre of this membrane is glued a little plate of platinum, which
stands in conductive communication with the clamping-screw _a_ by means
of a quite thin little strip of metal _f_ (distinctly visible in Fig.
349) [Fig. 31].
“Upon the middle of the little platinum plate, rests a short little
platinum pencil, which is fastened at _g_ to the under-side of the
strip of tin-plate _h g i_, one end of which, _h_, rests upon the
little metal pillar _l_, while a little platinum spike fastened upon
its under-side at _i_, dips into the hollow of the little metal pillar
_k_, containing some quicksilver. The clamping-screw _b_, is put into
conductive communication with the little metal pillar _k_.
“From one pole of the battery there goes a conducting-wire to the
clamping-screw _a_ of the interrupting apparatus Fig. 348 [Fig. 30],
from the other pole of the same there goes a wire to the clamping-screw
_d_ of the reproducing apparatus, Fig. 350 [Fig. 32], which is to be
presently described. The clamping-screw _c_, of this apparatus, is
connected by a wire with _b_, Fig. 348 [Fig. 30]. The clamping-screws
_c_ and _d_ are connected with the ends of the wire of the small
magnetising spiral M, Fig. 350 [Fig. 32]; with the connexion described
above, the current of the current-generator (battery) goes, therefore,
through the spiral M.
“As soon now as the sound-waves of an adequately powerful tone enter
through the mouth-piece S into the hollow cube A, the elastic membrane
which closes this at the top is set into vibrations. Each wave of
condensation on entering lifts the little platinum plate together
with the little spike which sits upon it; but if the membrane swings
downwards, the tin-piece _h g i_, with the little spike at _i_, cannot
follow it quick enough; there therefore occurs here, at each vibration
of the membrane, an interruption of the current which lets itself be
recognised by a little spark appearing at the place of interruption.
[Illustration: Fig. 30.]
[Illustration: Fig. 31.]
[Illustration: Fig. 32.]
“Now in the spiral M is stuck a knitting-needle, which, as the figure
shows, is fastened into a sounding-board. A lid provided with second
sounding-board may be clapped over the spiral, and the tone be thereby
greatly strengthened.
“If now, tones are produced before the mouth-piece S, whilst one sings
into the same or whilst one blows organ-pipes, one at once hears at the
reproducing apparatus a peculiar creaking noise which is independent of
the pitch of the tones produced at the interrupting apparatus, _but,
beside this, those tones are themselves reproduced by the steel wire
distinctly perceptibly_, and indeed Reis found that this is the case
for all tones between F and _f''_.
“In Reis’s experiments the interrupting apparatus was 300 feet distant
from the spiral, and was indeed set up in another house with closed
doors. But since the length of the conducting wire can be extended
just as far as in direct telegraphy, Reis gave to his apparatus
the name _Telephone_ (Jahresbericht des physikalischen Vereins zu
Frankfurt-a.-M. für 1860/61).”
[=15=.] EXTRACT FROM PISKO’S ‘DIE NEUEREN APPARATE DER AKUSTIK.’
[This book, ‘The more recent Apparatus of Acoustics,’ by Dr. Francis
Joseph Pisko, Professor of Physics in the Gewerbeschule in Vienna,
was published at Vienna in 1865. At that time the novelties in
acoustics were König’s apparatus for the graphic study of sounds,
König’s manometric flames, Schaffgotsch’s singing flames, Helmholtz’s
‘Researches on the Quality of Sounds,’ Duhamel’s Vibrograph, Scott and
König’s Phonautograph, and Reis’s Telephone. The account given of the
latter is more detailed in some respects than any other published at
the time.]
Page 94.--PRINCIPLE OF THE “TELEPHON” OF REIS.
51. (_a._) Allied to the Membrane Phonautograph is the “Telephon” of
Reis[34] (Fig. 33). Upon the little membrane, _m m_, in the middle,
is fastened with adhesive wax the round end _s_ of a light strip of
platinum, _n s_, so that the platinum strip can join in with all the
vibrations of the membrane. Very near to the central end, _s_, of the
little platinum strip, _n s_, a platinum spike stands, in such a way
that it is brought into contact, by the vibrations of the membrane,
with the platinum strip that vibrates with the latter. Suppose now that
the outer end, _n_, of the platinum strip and the platinum spike are
connected with the poles of a galvanic battery, then, by the vibration
of the membrane the galvanic current will, according to the phase of
the vibration, be alternately established and interrupted. Inserted
in this circuit, an electro-magnetic bell, or an electro-magnetic
telegraph, will give signals to great distances that somebody is
speaking;[35] though, obviously, it cannot inform _what_ is being
spoken.
[Illustration: Fig. 33.]
(_b._) As is known, an iron wire around which flow rapidly-interrupted
powerful galvanic currents, is thereby thrown into tones which,
according to circumstances, may be longitudinal or transverse or
both together. Such an iron wire, lying in a multiplying wire-coil,
_G_, Reis inserted at the second [receiving] station, _C_. The wire
emitted sounds when the membrane was set into vibrations by singing or
speaking (at _S_, Fig. 33) into the hollow cubical piece _A_. In the
investigations made by me with the telephone, the rod (of iron) never
altered the pitch of its tone with the most different kinds of tones
and clangs, and always gave only the rhythm of the words sung or spoken
into the piece _A_ (the transmitter) at _S_. Usually the air of the
song that was sung could be recognised by its rhythm.[36] The special
researches on these points follow in paragraph 53. However, it is so
far clear that there is still plenty of time yet before we have the
_simultaneous concerts_, and the transmission of singing to different
towns, as the daily newspapers have sanguinely expected. The apparatus
of Reis is certainly a “Telephone” but not a “Phonic Telegraph.”
The single means of transmission for song and speech--and that only
for moderate distances--remains the old familiar speaking-tube.
Nevertheless, the experiment of Reis must ever be reckoned amongst the
most beautiful and interesting of school-experiments. And since the
means for this are so simple, the apparatus of Reis will certainly
find a speedy entrance into educational establishments that are only
moderately endowed. It is easily proved that the tones of the wire in
the telephone do not arise from acoustic conduction, for by cutting out
the coil from the circuit the tones immediately cease.
1. The Telephone of Reis originally consisted of a cube of wood
with a conical boring. The smaller opening was strained over
with a membrane. A knitting-needle which served for a sounding
wire projected about 2 inches on each side of the multiplying
coil, and lay upon the two bridges of a sounding-box. The
surrounding helix consisted of six layers of thin wire. Fig.
33 shows the Telephone as it is constructed at the present
time by the mechanician, Albert, in Frankfort, and by the
mechanician, Hauck, in Vienna, according to the directions of
the inventor.
* * * * *
[52.] Details about the Telephone.
(_a._) The same (Fig. 33) consists in its essentials:
1. Of a transmitter, _A_;
2. Of a receiver, _C_;
3. Of a galvanic battery, _B_, and lastly,
4. Of the conducting wires that connect them.
(_b._) The transmitter, _A_, is essentially a parallelepipedal body
of wood. The upper part, _u x_, of it is cut out of one piece [of
wood] with square cross-section, the side, _x x_, of which measures 9
centimetres, and its height, _u x_, 2·8 centimetres.
This part is moveable upon a hinge on the lower little box, A A. If
the cover, _x u_, is laid back, one sees that a small circle of 3·9
centimetres diameter has been cut out in the same. Into this hole
passes a brass collar with a flange 8 millimetres broad, which is
furnished at one side with a groove like a pulley. Over the collar
there is stretched the membrane, _m m_, by means of a silk thread lying
in the shoulder of the same. This circular membrane is surrounded by
a wider circular aperture, _b b_, = 8·5 centimetres. A shovel-shaped
little strip of platinum, _n s_, lies (over it) leading to the brass
binding-screw, _d_, with the circular part, _s_, falling upon the
centre of the membrane.
By means of some sealing-wax this circular part is fastened to the
membrane, and thereby compelled to take part in the vibrations of the
same. The further transmission of the galvanic current from the centre
takes place by means of a platinum or steel point resting in a cup of
mercury, which is extended in a screw, which transmits the current
farther. The point _a_ serves as a support for the angular hook, _a
s b_, which in general is supported like a tripod, in order that the
point of contact, _s_, may remain as constant as possible. The hook, _a
s b_, is simply struck with a hole at _a_ upon a projecting point, and
lies upon a broader under part. From _b_ the galvanic circuit proceeds
by means of an overspun wire to the brass key _e_ (A, Fig. 33), and
from there farther in the direction represented by the arrow.
The lower part A A of the transmitter is put together of thin wood and
forms a parallelepiped, whose height = 6·8 cm., and whose width = 7·7
cm. An inclined mouthpiece of tin with funnel-shaped opening serves
to receive the tones. The longer side of this mouthpiece measures 6·7
cm., the shorter 4·7 cm.; the longer diameter of the widening measures
7·15 cm., the shorter diameter 7·5 cm., and finally the diameter of the
narrow tube 3·9 cm.
It is clear that, if necessary, the platinum strip can be
replaced by a strip of thin sheet-brass, the platinum or steel
points by iron. Only in this case the points of contact must be
oftener cleaned to a metallic polish.
(_c._) The receiver (Zeichengeber) C is in general a double resonant
box, whose upper part, “the cover,” is moveable upon two hinges, and
can be laid back. The length of this cover is 16·4 cm., its width 9·5
cm., and its height 3·2 cm. The length of the lower box measures 22·9
cm., its width 9·6 cm., and its height 2·5 cm. The under part of the
resonant box bears two wooden bridges, which stand about 7·4 cm. from
each other, and which serves as supports for the 21·5 cm. long, and 0·9
cm. thick iron needle destined for reproducing the tones. The length of
spiral wound over the needle, and designed for making an electro-magnet
of the same, is 15 cm. The wooden covers of both parts, scraped as
thin as possible, and the greatest breadth of the circular holes shown
in the figure, measures 13 mm.
(_d._) For a battery one can successfully use a small Smee’s consisting
of four elements, or two larger Bunsen’s cells.
The conductor must be at least sufficiently long that one cannot
perceive the tones that are produced. For correspondence between the
two stations the inventor has employed the electro-magnetic telegraph
arrangement, _e v g h_, seen in the mechanism, and easily understood.
An agreement in reference to corresponding signs can be easily
arranged, and the simplest way is to accept the signals arranged by the
inventor. (See ‘Prospectus.’)
The receiver C gives, when the key _e_ is pressed, the corresponding
telegraphic signals by means of tones in the rod E E, while at the
transmitter, A, the electro-magnet _v_ gives the signals by means of
the springy armature _z_.
[53.] Experiments with the Telephone.
(_a._) As soon as one brings the mouth to the funnel S and sings, the
membrane of the transmitter, A, vibrates in a corresponding manner, and
the iron rod, E E, at the second station begins to give forth a tone.
Every time a spark is seen at the first station _s_, the rod at the
other station certainly gives forth a tone. The same is true when one
hears the peculiarly snarling tone which arises from the stroke of the
vibrating platinum strip against the spike of angular hook resting upon
it.
The appearance of these sparks or of the peculiar snarling at the
transmitter A gives the sign to the observers at the station A that
the rod in C is giving a tone. Tones and melodies which were sung into
the sound aperture, and especially sounds in which the teeth and bones
of the head also vibrated (so-called humming tones), always evoked
a tone in the rod or needle E E, and indeed, as already mentioned (§
51), without change in the pitch, but only with the reproduction of the
rhythm of the respective song or words.
The pitch of the tone excited at C in the rod E E was in the apparatus
at my disposal _h_; its strength not very great and its clang snarly,
similar to that of a lightly sounding reed-whistle, somewhat like that
of a child’s wooden trumpet. The cuticle lying about the heart of the
smaller and even the larger mammals (from calves, &c.) makes the best
membranes. Goldbeater’s-skins reproduce only the deeper tones. The
cover of the sounding-box appeared in my apparatus superfluous, and
indeed the tone was somewhat stronger without the cover.
1. In experiments with the telephone, one must look closely
as to whether the ends of the platinum strip is still
fastened to the membrane, and one must, if necessary, press
upon the membrane. If the strip will no longer stick, heat
a knife-blade, touch a small piece of sealing wax with it,
and carry thus the melted sealing-wax to the under side of
the round end of the platinum-strip, _n s_. Then press it
immediately on the membrane, _m m_.
Ph. Reis showed his apparatus in very primitive form for
the first time in October, 1861, to the Physical Society at
Frankfort-on-the-Main; on July 4th, 1863, before the same
society, he showed the form represented in Fig. 33. This time
he experimented upon a distance of 300 feet. Professor Boettger
brought the apparatus before the Naturforscher-Versammlung at
Stettin (1863) in the section for Physics.
[=16.=] HESSLER’S ‘TEXT-BOOK OF TECHNICAL PHYSICS,’ vol. i. p. 648.
[Next in chronological order comes a notice of the Telephone in
Hessler’s ‘Lehrbuch der technischen Physik,’ edited by Prof. Pisko,
and published at Vienna in 1866. The brief account given in this work
adds nothing to the accounts previously given, and is evidently written
by some person ignorant of Reis’s own work, for beside omitting all
mention of the transmission of speech by the instrument, or of its
being constructed upon the model of the human ear, the writer appears
not even to know how to spell Reis’s name,[37] and speaks of him as
“Reuss.”]
[=17.=] KUHN’S ‘HANDBOOK OF APPLIED ELECTRICITY,’
(‘Handbuch der Angewandten Elektricitätslehre,’ von Carl Kuhn), being
vol. xx. of Karsten’s ‘Universal Encyclopædia of Physics’ (Karsten’s
‘Allgemeine Encyclopädie der Physik’).
[Karsten’s ‘Encyclopædia of Physics,’ which has been for many years
a standard work of reference, both in Germany and in this country,
consists of a number of volumes, each of which is a complete treatise,
written by the very highest authorities in Germany. Thus Helmholtz
contributed the volume on Physiological Optics, Lamont that on
Terrestrial Magnetism, whilst the names of Dr. Brix, Professor von
Feilitzsch, and others, are included amongst the authors. Carl Kuhn,
who wrote vol. xx., was Professor in the Royal Lyceum of Munich, and
member of the Munich Academy. Kuhn’s volume on ‘Applied Electricity,’
published in 1866, is to be found on the shelves of almost every
library of any pretensions in Great Britain. The account given therein
of Reis’s Telephone is interesting, because it describes two forms,
both of transmitter and of receiver. In fact the descriptions and
figures are taken almost directly from von Legat’s Report (p. 70), and
from Reis’s Prospectus (p. 87). The extract translated below includes
all the matter that is of importance.]
P. 1017. The researches established by Reis on the 26th of October,
1861, in Frankfurt[38] have already shown that if the current
interruptions follow one another almost continuously and very rapidly,
in a spiral arranged with a thin iron core, the iron wire can be set
into longitudinal vibrations, whereby therefore the same is constrained
to reproduce tones of different pitch.
* * * * *
[Here follows a reference to Petrina’s Electric Harmonica.]
* * * * *
From the communications made known by Legat, it follows that “the ideas
concerning the reproduction of tones by means of electro-galvanism
which were put forward some time since by Philipp Reis of
Friedrichsdorf, before the Physical Society, and the meeting of the
Free German Institute in Frankfort-on-the-Main,” relate to similar
arrangements. “What has hitherto been attained in the realisation of
this project,” Legat announces in his report, and we extract therefrom
only that part which gives an explanation of the disposition of the
telegraphic apparatus, with which it is said to be possible to produce
the vibrations and the excitement of tones in any desired manner,
and by which the employment of electro-galvanism is said to make it
possible “to call into life at any given distance vibrations similar to
the vibrations that have been produced, and in this way to reproduce at
any place the tones that have been originated at another place.”
This apparatus consists of the tone-indicator (transmetteur) and
the tone-receiver (récepteur). The tone-indicator (Fig. 34, p. 109)
consists of a conical tube, _a b_, having a length of about 15 cm., a
front aperture of about 10 cm., and a back aperture of about 4 cm.,
the choice of the material and the greater length of which is said to
be indifferent, while a greater width is said to be injurious; the
surface of the inner wall should be as smooth as possible. The narrow
back aperture of the tube is closed by a membrane, _o_, of collodion,
and upon the centre of the circular surface formed by this membrane
rests the one end, _c_, of the lever, _c d_, the supporting-point
of which, _e_, being held by a support, remains in connection with
the metallic circuit. This lever, the arm, _c e_, of which must be
considerably longer than _c d_, should be as light as possible, so
that it can easily follow the movements of the membrane, because an
uncertain following of the lever, _c d_, will produce impure tones at
the receiving station. During the state of rest the contact, _d g_, is
closed, and a weak spring, _n_, keeps the lever in this state of rest.
Upon the metallic support, _f_, which is in connection with one pole
of the battery, there is a spring, _g_, with a contact corresponding
to the contact of the lever, _c d_, at _d_, the position of which
is regulated by means of the screw, _h_. In order that the effect
of the apparatus may not be weakened by the produced waves of air
communicating themselves towards the back part, a disc “of about 50
(?) cm. diameter, which rests fixedly upon the exterior wall of the
tube,” is to be placed above the tube, _a b_, at right angles with its
longitudinal axis.
[Illustration: Fig. 34.]
The tone-receiver consists of an electro-magnet, _m m_, which rests
upon a resounding-board, _u w_, and the surrounding coils of which
are connected with the metallic circuit and the earth. Opposite to
the electro-magnet there stands an armature, which is connected with
a lever, _i_, as long as possible but light and broad, and which
lever together with the armature, is fastened like a pendulum to
the support _k_; its movements are regulated by the screw _l_ and
the spring _q_. “In order to increase the effect of the apparatus,
this tone-receiver may be placed in the one focus of an elliptically
hollowed cavity of sufficient size, while the ear of the person who
listens to the reproduced sounds ought to be placed at the second focus
of the cavity.” The action of the two apparatus, the general manner
of connection of which may be seen from the illustrations--at the one
station being the tone-indicator, at the other the tone-receiver--is
the following:--By speaking into, singing, or conducting the tones
of an instrument into the tube, _a b_, there is produced in the
tone-indicator (Fig. 34) in consequence of the condensation and
rarefaction of the enclosed column of air, a motion of the membrane,
_c_, corresponding to these changes. The lever, _c d_, follows the
movements of the membrane, and opens or closes the circuit according
as there occurs a condensation or rarefaction of the enclosed air. In
consequence of these actions, the electro-magnet, _m m_ (Fig. 13),
is correspondingly demagnetised or magnetised, and the armature (and
the armature-lever) belonging to it is set into vibrations similar to
those of the membrane of the transmitting apparatus. By means of the
lever, _i_, connected with the armature, the similar vibrations are
transmitted to the surrounding air, and these sounds thus produced
finally reach the ear of the listener (the sounding-board increasing
the effect). As regards the effectiveness of this apparatus, the author
remarks that while the similar number of the produced vibrations is
reproduced by the receiver, their original strength has not yet been
obtained by it. For this reason also small differences of vibration
are difficult to hear, and during the practical experiments hitherto
made, chords, melodies, &c., could be, it is true, transmitted with
astonishing (?) fidelity, while single words in reading, speaking, &c.,
were less distinctly perceived.
* * * * *
[The rest of the article deals with the “square-box”
transmitter described in Reis’s Prospectus, and adds nothing to
the information already published.]
[This is the last of the contemporary documents bearing upon the
performance of Reis’s instruments. From the prominent notice obtained
at the time by the inventor, it is clear that his invention was even
then accorded an honourable place amongst the acknowledged conquests
of science. A critical examination of this body of evidence proves not
only the substantial nature of Reis’s claim, but that the claim was
openly recognised and allowed by the best authorities of the time. The
thing was not done in a corner.]
FOOTNOTES:
[15] [This was the number formerly accepted on the authority of
Despretz as the minimum number of vibrations that could evoke the
sensation of a tone in the human ear. The limit now more usually
recognized is that of Helmholtz, who assigns from thirty to forty
double vibrations per second as the minimum.]--S. P. T.
[16] [The three plates or tables with which Reis accompanied his
Memoir, containing a variety of undulatory curves corresponding
to various combinations of tones, both of musical concords and of
dissonant sounds, are not reprinted in this book in their entirety.
Table I. contained three sets, the first of which is reproduced by
photo-lithography in reduced facsimile in Fig. 47, p. 173. It was also
reproduced by W. von Legat in his Report from which Plate I. at end of
this book is copied, Fig. 1 of that plate being the same as Fig. 1 of
Reis’s Table I. Fig. 2 of Plate 1, was in like manner copied by Legat
from the first figure of Reis’s Table II., and Fig. 3 of Plate I.,
which represents the curves of a non-harmonious combination is the same
as Reis’s Table III., the only difference being that in Reis’s Table
III. the irregular undulations of the resultant curve were emphasised
by being labelled ‘Dissonanz.’]--S. P. T.
[17] [This is true for speech-tones as well as for musical tones. Each
kind of tone may be represented by its own characteristic curve.]--S.
P. T.
[18] [This is the fundamental principle, not only of the telephone, but
of the phonograph; and it is wonderful with what clearness Reis had
grasped his principle in 1861.]--S. P. T.
[19] [That is, at any single demagnetisation of the needle, it vibrates
and emits the same tone as if it had been struck or mechanically caused
to vibrate longitudinally.]--S. P. T.
[20] [This range was simply due to the degree of tension of
the tympanum; another tympanum differently stretched, or of
different proportions, would have a different range according to
circumstances.]--S. P. T.
[21] [The so-called “galvanic tone” heard on opening or closing the
circuit _was_ well-known, and Wertheim had shown that this tone
was, for any given rod of iron, identical with its “longitudinal
tone,” _i.e._ the tone produced by striking it on the end so as to
produce longitudinal vibrations. But it was one of the most important
discoveries in Reis’s researches that such a rod could take up _any_
tone in obedience to the vibrations forced upon it by periodic
interruptions in the magnetising current in the spiral of any degree of
rapidity within very wide limits. The translator has had occasion to
examine this point, and has found iron, steel, and cobalt wires varying
from 4 to 10 inches in length, including some used by Reis himself as
receivers, to be capable of taking up vibrations from as slow as 40
per second to the very shrillest whistle audible to human ears, or
exceeding 36,000 per second. It is sometimes also mistakenly supposed
that such a wire can respond only to the vibrations of tones that are
musical, not to those that are articulate, including both consonants
and vowels. This, however, is an entire mistake. For, using such a
wire as a receiver (surrounded by its proper coil and mounted with an
appropriate sounding board, or, better still, tympanum), in conjunction
with a well-adjusted transmitter, the articulation transmitted
surpasses that obtainable with any of the ordinary magnetic receivers
in distinctness, though not in loudness. This discovery of Reis’s is of
the greatest importance, especially as some who ought to know better
have very unjustly denied the capability of this part of the apparatus
to act as a telephone receiver for articulate sounds.]--S. P. T.
[22] [This limit is a mistake of Professor Böttger’s. The longitudinal
tone of an unstrained iron or steel wire 10 inches long would be a
note about four octaves above the middle _c_ of the piano; whereas, in
fact, any note of the whole piano-gamut down to the lowest note, can be
reproduced by such a wire, as stated in preceding footnote.]--S. P. T.
[23] [Professor Böttger had not to wait long for the fulfilment to a
very large degree of this anticipation; for within six months Dingler’s
Journal, in which this article appeared, contained Legat’s report
on Reis’s instruments, in which not only were various modifications
in their construction made known, but also the transmission of
voice-tones, not yet perfectly but with recognisable modulations and
intonations, was recorded. Reis had, indeed, succeeded nearly as well
as this with his first instrument, as his memoir of 1861 shows. See p.
58.]
[24] [Compare ‘_Die Geschichte und Entwickelung des Fernsprechwesens_,’
a pamphlet issued officially in 1880 from the Imperial German
Post-Office in Berlin, p. 6.]
[25] [Plate VIII. of the original in Vol. IX. of the Zeitschrift.]
[26] [Plate IX. of the original Memoir.]
[27] [This word, as the context and ending of the paragraph shows,
should have been spelled _tones_. The letter, written in English by
Reis himself, is wonderfully free from inaccuracies of composition;
the slip here noted being a most pardonable one since the plural of
the German “_ton_” is “_tönen_,” the very pronunciation of which would
account for the confusion in the mind of one unaccustomed to write
in English. So far as is known, this is the only piece of English
composition ever attempted by Reis.--S. P. T.]
[28] [Reis here sketched a figure identical in all its parts with that
which a fortnight later was issued in his ‘Prospectus.’ His sketch is
reproduced in facsimile in Fig. 28.]
[29] [This was the little auxiliary signalling apparatus at the side of
the box, placed there for the same reasons as the auxiliary call-bell
attached to modern telephones.]
[30] [This word is underscored in Reis’s original letter.]
[31] [Compare Böttger Polyt. Notizbl. 1863, p. 81, the notice
translated at p. 61 preceding.]--S. P. T.
[32] [This rather obscure passage refers to the call-key or
communicator fixed to the side of the instruments, and which as the
inventor explains in his Prospectus (see p. 87), to be intended, like
the call-bell or communicator of modern telephones, as a means of
sending signals to the speaker, and which, as the Prospectus says,
can also be used--as any call-bell can--for telegraphing words by a
pre-arranged code of signals.]--S. P. T.
[33] [Fig. 30 of this book.]
[34] [References.] _Telephon von Reis_ im Jahresbericht des
physikalischen Vereins zu Frankfurt-a.-M. für 1860-1861, pag. 57 bis
64. _Müller-Pouillet_, Physik, 1863, 6. Auflage, II pag. 352, Fig. 325.
_Berl. Ber._ für 1861, xvii. pag. 171 bis 173. Der Musiktelegraph in
der “Gartenlaube” 1863, Nr. 51, pag. 807 bis 909. Aus der Natur 1862,
xxi. pag. 470 bis 484; _König’s_ Catalog, 1865, pag. 5.
[35] [This part of the apparatus is in fact a “call,” serving precisely
the same function as the call-bell attached to ordinary telephones, by
which the subscriber can be “called up” to listen to the instrument. It
is not without importance to observe that this function was perfectly
well-known at the time; for it was gravely argued during a former
telephone law-suit in England that the presence of this “signal-call”
at the side of the Reis Transmitter was a proof that it was intended
to transmit singing only _and not speech_, or “else there would not
have been that little Morse-instrument at the side by which to talk”!
This suggestion is, however, self-evidently absurd, because if this
had been the case the little electromagnetic Morse telegraph would
have been fixed, not on the side of the transmitter but on that of the
receiver. Reis himself explains the use of the “call” (see p. 87) in
his “Prospectus.”]--S. P. T.
[36] [Professor Pisko seems to have got hold of an unusually
unfortunate specimen of the instrument if he could make it neither
speak nor sing. His transmitter must have been in exceedingly bad
condition to fail so completely.]
[37] This error has been copied by Count du Moncel, along with
the other defects of the article, into the fifth volume of his
‘Applications of Electricity,’ published in 1878. It is rather amusing
now to read, at p. 106, of Du Moncel’s treatise that “Heisler” (_sic_)
“pretends” that the telephone of “Reuss,” which “appears” to have been
invented “anterior to the year 1866,” was capable of transmitting vocal
melodies! Count du Moncel, though he has since posed as an authority on
the telephone, did not in 1878 shine in that capacity, for on the very
same page of the Count’s book may be found the following astounding
sentiment:--“_If it is true_, as Sir W. Thomson has assured us, _that
at the Philadelphia Exhibition of 1876 there was a telegraphic system
transmitting words_, we may recognize,” &c. Count du Moncel has since
found out that it _is_ true that there was a Telephone in Philadelphia
in 1876: perhaps he will next discover that “Reuss” did, “anterior to
the year 1866,” actually “appear” to transmit not only what “Heisler”
“pretends” he did, but that he also transmitted spoken words.--S. P. T.
[38] Ueber Fortpflanzung der Töne auf wilkührlich weite Entfernungen,
mit Hülfe der Elektricität (Telephonie). Polyt. Journ. clxviii. 185;
aus Böttger’s Notizbl. 1863, Nr. 6. [See translation on page 61.]